I remember using this argument against the proposed creationism view of my religion teacher. If it is possible for life to emerge on a planet, given enough time, it is bound to happen. Likewise: given enough games of Go, one game will end with a perfectly ordered black-white spiral. This then led to the tangent of: Is it possible for God to exist in our world?
The same with the possible worlds model of modal logic. If something is possible, there is a world were such is the case. That could mean that, if time travel or travel between possible worlds is possible, there is a world out there, where they discovered this. They could travel between possible worlds and teach these other worlds how to travel too.
As soon as something that crosses the boundaries between worlds is even remotely possible, in the end it should permeate through all possible worlds.